This invention relates to a spool for storing and dispensing filamentary material such as corona wire for a photocopy machine. More specifically, the present invention relates to a spool having a resilient tab for capturing a loose end of the filamentary material.
Spools have long been employed for loading, storing and dispensing thread, yarn, wire and other filamentary material. Some spools have incorporated a retainment feature to capture the loose end of the filamentary material. For example, Bruestle U.S. Pat. No. 2,776,097 discloses a cutting and clamping mechanism which consists of a movable plate slidably mounted in a guideway formed in a disc-like spool head. The cutting and clamping mechanism is urged radially outward from the spool head by the centrifugal force generated by the spinning spool. As the spinning spool is loaded with wire and becomes full, the wire is crossed over to a spinning empty spool. The wire is cut and clamped by the extended cutting and clamping head. As the spool comes to a stop, the centrifugal force generated by the spinning spool is overcome by the centripetal force supplied by a spring. The cutting and clamping head retracts radially inward and retains the wire temporarily until it can be retained by more suitable means.
Deroseau U.S. Pat. No. 766,936 discloses a spool with a retainment feature for storing and dispensing chalk line. The spool includes a drum having laterally extending end flanges with a traverse recess in one of the flanges. The retainment feature is implemented by employing two clamping plates, a first clamping plate attached securely to the flange that includes the traverse recess, and a second resilient plate, normally in contact with the first plate, connected to a spring loaded stud which extends through the traverse recess to a stop button located on the opposite side of the flange. The chalk line is clamped by depressing the stop button to separate the plates, positioning the chalk line between the plates, and releasing the stop button, thereby allowing the spring loaded stud to urge the second plate toward the first plate clamping the chalk line.
Other devices such as Mahoney U.S. Pat. No. 3,810,588 and Temple U.S. Pat. No. 1,029,5I8 employ protective covers or housings which include a retainment feature for capturing the loose end of a filamentary material. However, these inventions do not include the retainment feature in the spool itself.
These devices, however, are generally not suitable for storing and dispensing delicate filamentary material such as corona wire. Corona wire is used in plain paper copiers, laser printers and plain paper facsimile machines utilizing the basic xerographic process to distribute an electric charge onto various surfaces. Spools that have been used in the past for storing corona wire include a retainment feature which is either ineffective, or tends to kink or tangle the wire. If the corona wire becomes kinked or tangled, that segment of the corona wire must be discarded. The retainment feature has been implemented in various ways.
In one implementation, the wire is retained by forcing the wire into a slot in the side of the spool made of a soft plastic material. The wire is kinked at the point at which it is forced into the slot. In another implementation, an adhesive sticker is used to hold the loose end of the corona wire to the side of the spool. While this implementation does not produce a sharp kink in the wire, the application of the sticker to the side of the spool is awkward and may lead to the user tangling the wire. Also, the adhesive properties of the sticker decline with continued use. A third implementation of the retainment feature is to employ a cap which fits firmly within an inner hub of a spool to clamp the wire between an outer cap surface and an inner hub surface. This implementation produces two sharp kinks in the corona wire.